The invention relates to a pistol with an interchangeable barrel to be converted to different projectile calibers, so that ammunition with a smaller caliber can be used, for example for training purposes.
In conventional pistols of this type, the breech surface confronting the cartridge base, that is to say the so-called concussion base, has a shallow, essentially circular recess for receiving the cartridge base. This recess is limited, on one side, by a pull-out claw, by means of which the cartridge case is grasped at the cartridge base and pulled out of the barrel when the breech is moved back relative to the barrel, after the locking of the breech has been cancelled. The grip piece or housing of the pistol is equipped, on that side of the breech located opposite the pull-out claw, with a rigid ejector which, during the rearward movement of the breech and of the cartridge case, butts against the cartridge base, so that the cartridge case is ejected on the side on which the pull-out claw is located.
In this conventional construction, the breech of the pistol is therefore specially adapted to the dimensions of the cartridge base of the ammunition used. The disadvantage of this is that, despite the exchangeability of the barrel, only ammunition with a uniform cartridge base can be used. Only the projectile caliber and the shape of the cartridge case can consequently be varied.
In many conventional pistols, for example in Colt pistols, the breech is released by means of two links which are arranged on both sides of the rear end of the barrel and which are fastened at their lower end in an articulated manner to a bolt on the grip piece of the pistol and at their upper end in an articulated manner to the barrel. When the barrel moves backwards as a result of the recoil after a shot has been fired, these links bring about a semicircular rearward and downward movement of the rear end of the barrel, while the breech moves in a straight line in appropriate guides of the grip piece. Locking grooves and locking projections arranged on the top of the barrel come out of corresponding grooves and projections of the breech, so that the locking between the barrel and breech is cancelled.
The disadvantage of this construction, especially in pistols with an interchangeable barrel, is that it is relatively complicated to change the barrel. Another disadvantage is that, as a result of the action of the links, a certain pivoting of the barrel occurs even before the projectile has left the barrel, and the aiming accuracy of the weapon is therefore impaired.